# Networking >  network device

## abhishek.masyuni

layer 3 switch workes witch layer?

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## kaypee_ccna

Network layer

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## monami85

> Network layer


here it is 
     NETWORK LAYER :---
                                  This layer is third layer of osi model. this layer convert the segments fromthe transport layer to packets and also responsible for path determinations and routing and also responsible for logical addressing (also known as network address or layer 3 address) eg; ip address...
\    protocol defined at this layer are ip,ipx icmp,rip, bgp,ospf
     devices operate at this layer are routers and swithes ( only layer 3 swithes) thats it.....

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## monami85

layer 3 switch work at network layer 
layer 2 switch work at datalink layer

   layer 3 switches using network address for filtering and forward packets
   layer 2 switches usind MAc address for filtering and forward packets

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## monami85

any more queations dont hesitate just ask me

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## dinesh_boora

> layer 3 switch workes witch layer?


switch works on the layer data link layer

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## Sushma Mosali

hi,

The network layer determines that how data transmits between the network devices. It also translates the logical address into the physical address e.g computer name into MAC address. It is also responsible for defining the route, managing the network problems and addressing. Router works on the network layer and if a sending device does not break the data into the similar packets as the receiving device then network layer split the data into the smaller units and at the receiving end the network layer reassemble the data.

Network layer routes the packets according to the unique network addresses. Router works as the post office and network layer stamps the letters (data) for the specific destinations. 
Protocols: These protocols work on the network layer IP, ICMP, ARP, RIP, OSI, IPX and OSPF. 
Network Devices: Network devices including Router, Brouter, Frame Relay device and ATM switch devices work on the network layer. 

Thanks
Sushma

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## deepasree

Hi friend.. 

Definition of: layer 3 switch a network device that forwards traffic based on layer 3 information at very high speeds. Traditionally, routers, which inspect layer 3, were considerably slower than layer 2 switches. In order to increase routing speeds, many "cut-through" techniques were used, which perform an "inspect the first packet at layer 3 and send the rest at layer 2" type of processing. Ipsilon's ip switch and cabletron's securefast switches were pioneers in cut-through switching. 

From software to hardware as more routing lookup functions were moved from software into the asic chips, layer 3 switches could inspect each packet just like a router at high speed without using proprietary cut-through methods. If a layer 3 switch supports packet-by-packet inspection and supports routing protocols, it is called a "routing switch" or "switch router," which simply means "fast router." for example, cisco calls its high-end routers gigabit switch routers. More inspection takes time the more deeply a packet is examined, the more forwarding decisions can be made based upon type of traffic, quality of service (qos) and so on. T

o obtain this information requires digging into the packet's headers to ferret out the data, which takes processing time. To understand how packets are formed, see tcp/ip abc's. 

The following shows what data is examined at each layer. Forwarding decision layer based on examples 2 mac address ethernet, token ring, etc. 3 network address ip, ipx, etc. 3 service quality ip, ipx, etc. 3 application ipx socket 4 application ip socket 

thanks 
deepasree

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## ramhppatil

network device

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## purusharma

this is 3rd layer from bottam to top in osi modal
this layer is impotant layer
in this network types shown

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## mukulsingh

> any more queations dont hesitate just ask me


can u tell me that how can i difine that what is subnetmask , why it is must in networking and what is the working of it?

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## Laxmidhar123

Hi 

Switch is a (layer -2 device ) used in data link layer.

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## amit_841984

layer 3 switch is completely work in network layer of osi model

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